The present invention relates to an absorption refrigerating machine, and more particularly to an absorption refrigerating machine characterized by a system for supply of cooling water to an absorber and a condenser.
Generally, cooling water for an absorption refrigerating machine has heretofore been flowed in series to an absorber A and a condenser C by a shell and tube system, as shown in FIG. 4.
In FIG. 4, a concentrated solution changes into a dilute solution by absorbing, in the absorber A, a refrigerant vapor evaporated in an evaporator E. The dilute solution is passed through a passage 1 and a heated side of a solution heat exchanger SH, and then introduced into a regenerator G via a passage 2 by a solution pump SP. The dilute solution introduced into the regenerator G is heated by a heat source 12 to evaporate the refrigerant, so that the dilute solution changes into a concentrated solution. The concentrated solution is passed through a passage 3 and a heating side of the solution heat exchanger SH, and then introduced via a passage 4 into the absorber A, where the concentrated solution absorbs a refrigerant vapor again to change into a dilute solution. Thus, the solution is circulated.
On the other hand, the refrigerant becomes a refrigerant vapor by being evaporated in the regenerator G. The refrigerant vapor reaches the condenser C, where the refrigerant vapor is condensed into a refrigerant liquid, which is introduced into the evaporator E via a passage 5. While the introduced refrigerant liquid is circulated into the evaporator E via a passage 6 by a refrigerant pump FP, the refrigerant liquid is evaporated in the evaporator E for cooling chilled water 11. The evaporated refrigerant reaches the absorber A, where the refrigerant is absorbed into the concentrated solution. The absorbed refrigerant reaches the regenerator G, where the refrigerant is evaporated. Thus, the refrigerant is circulated. The cooling water is introduced through a passage 7, passed through the absorber A and the condenser C, and is discharged through a passage 10.
In this case, the amount of cooling water flowed is determined one-sidedly by the required amount of cooling water in one of the absorber and the condenser.
When a large number of plate type heat exchangers are stacked and used for exchanging heat in an absorption refrigerating machine, a large flow rate requires a large passage area between the plates, so that the efficiency of heat exchange is lowered. Therefore, when a plate type heat exchanger is employed for heat exchange in the absorption refrigerating machine, it is advantageous to minimize the flow rate and reduce the required passage area.
When cooling water is flowed through an absorber and a condenser of an absorption refrigerating machine, the flow rate of the cooling water flowed into respective heat exchangers can be made smaller in the case of flowing in parallel than in the case of flowing in series. Thus, when the plate type heat exchangers are used, it is more advantageous to flow cooling water in parallel. However, there has not been known a system in which plate type heat exchangers are used in an absorber and a condenser for an absorption refrigerating machine and cooling water is flowed therethrough in parallel.
When cooling water is flowed in parallel, in order to match the flow rates introduced into an absorber and a condenser with design values, a flow regulating valve may be provided in a cooling water passage to adjust the flow rates by a passage resistance generated by the flow regulating valve. However, it is complicated to adjust the flow regulating valve based on fluctuations in the water pressure, causing operational problems.
The present invention has been made in view of the above drawbacks, and it is therefore an object of the present invention to provide an absorption refrigerating machine which uses plate type heat exchangers in an absorber and a condenser, and can adjust the amount of distribution of cooling water without a flow regulating valve provided in a cooling water passage, and has no operational problem.
To solve the above problems, according to an aspect of the present invention, there is provided an absorption refrigerating machine using plate type heat exchangers at least in an absorber and a condenser, characterized in that cooling water is supplied in parallel to the plate type heat exchangers in the absorber and the condenser, and amounts of cooling water distributed to the absorber and the condenser are determined mainly based on fluid resistance of each of the plate type heat exchangers.
According to another aspect of the present invention, there is provided an absorption refrigerating machine using plate type heat exchangers in an absorber and a condenser, characterized in that cooling water is supplied in parallel to the plate type heat exchangers in the absorber and the condenser via a cooling water passage, and a flow regulating valve for distributing cooling water to the absorber and the condenser is not provided in the cooling water passage, but cooling water is directly supplied via the cooling water passage to the absorber and the condenser.
In the absorption refrigerating machine, the plate type heat exchangers used in the absorber and the condenser should preferably have the same shape of the plates and the different number of plates. Further, a ratio of the number of plates in the absorber to the number of plates in the condenser should preferably be in the range of 67:33 to 60:40.